1. Field of Art
This invention relates to the improvement of an agricultural harvesting machine. More specifically it relates to an improvement to the mechanism for rotating and affixing the tongue relative to the trailframe on a pull type agricultural implement.
2. Description of Prior Art
Pull type mowers and mower conditioners have been used in farming operations for decades. The mower is designed to cut and process hay or other crops. If desired, the processed crop can be placed in a windrow for drying and later processing. Typically, the mower or mower-conditioner is towed and powered by a tractor. The mower has a cutting means that is powered by the power-take-off shaft of the tractor. The cutting means can consist of a sickle bar or rotary disc mower. Such cutting means are well known and well described in the prior art. If desired, the cut crop can be conditioned or ejected from the mower. The stem portion of a conditioned crop is usually crimped so as to allow the moisture in the stem to escaped. If conditioned crops are desired, the crops are passed through a pair a rubber covered conditioning rolls or through a set of metal flails. The ejected crop is arranged onto a windrow to aid in drying. These methods are well known and described in the prior art. The processed crop is left on the field for future processing--usually a baling mechanism of some type.
As previously indicated the mower and conditioning rolls are powered by the PTO and/or a hydraulic pump on the tractor. Connecting the tractor to the mower or implement is a pivoting tongue. The tongue may be positioned so as to allow the implement to remain directly behind the tractor or to the left or right side of the tractor. Previously, the width of the mower was small enough to allow an operator to tow the implement directly behind the tractor (the standard transportation mode) without any difficulties. However, to improve efficiencies, the cutting means continues to be increased in width. The cutting means on many implements are now too wide to safely transport down a roadway using the standard transportation mode.
To assist in the transport of these large mowers and implements, the implement is backed onto a transporter or trailer and the tongue is pivoted 90 degrees from the standard transport position. This lateral transport positioning of the tongue allows the implement to be safely towed down a roadway. A hydraulic cylinder attached between the implement's trailframe and tongue accomplishes the pivoting of the tongue 90 degrees from the standard transport position to the lateral transport position. The hydraulic cylinder is actually rotating the entire implement and trailer relative to the tongue. As the hydraulic cylinder is retracted, a significant hydraulic force is required to rotate the implement and trailer. Typically, there is very little mechanical advantage left at the end of the cylinder stroke by the time the implement has rotated towards 90 degrees. As a result, it is difficult for the hydraulic cylinder to shift the implement the final few degrees or to begin to shift the implement the other direction when needed.
After the implement is rotated into the lateral transport position, the implement needs to be secured to the tongue. Prior art attachment mechanisms have been complicated and difficult to attach.
The prior art illustrates these and other difficulties with current art. U.S. Pat. Nos. 3,721,461 and 4,607,996 illustrate lateral transport trailers such as discussed above. As noted, the hydraulic cylinder used to rotate the implement 90 degrees relative to the tongue required a high force due to the poor mechanical advantage. U.S. Pat. Nos. 4,558,560 and 5,642,607 disclose conventional tongue and implement rotation approaches. As can be seen, the hydraulic cylinder has very little mechanical advantage when the tongue is in the lateral transport position.
Consequently, the need exists for an improved mechanism for swinging the tongue into the lateral transport position and for affixing the tongue to the trailframe to allow for safe transport of a wide mower or similar pull type implement.